UPT is an abbreviation of Universal Personal Telecommunication. When a person has a UPT number and another subscriber dials the UPT number, the incoming call may be connected to a local fixed telephone, an automatic pager, a mobile phone, a voice mailbox that can be directly dialed in, etc. A UPT application server may further set various forward numbers (Forwarding on Busy, Forwarding on Schedule, etc.) via a management interface. A subscriber may register an office telephone number and a mobile phone number according to his/her work and rest practice so that a call may be forwarded to an office telephone during working time or to a mobile phone at other time.
On the existing telecommunication market, integrated solutions to the color ring back tone service have been developed for the Global System for Mobile communications (GSM) network, the Code Division Multiple Access (CDMA) network and the fixed telephone network, respectively. Such solutions may be classified into intelligent network solutions, end office solutions, and so on. In all of these solutions, any ring back tone is provided from the home network of the subscriber, thus causing some inflexibility. In addition, the UPT application server and the ring back tone service are deployed separately and thus independent of each other. In the existing ring back tone services, usually a media resource server of the home network of the called subscriber can be previously configured to provide a ring back tone service for the subscriber, and it is not possible to dynamically select an optimal media resource server for a current call according to the information on the caller and the called as well as the ring back tone per se, resulting in the waste of the network resources to some extent. On the other hand, the subscriber cannot configure ring back tone information flexibly for different destination numbers corresponding to his/her UPT.